Article No: 149

2006-05-03 08:41:23
Texas Hill Country ranch taps concrete benefits
By: Carole McMichael

Photography courtesy of Matt Bachardy

The vastness of Texas is home to western deserts, eastern pine forests, central plateaus and coastal plains. Where the coastal plains meet the plateau country runs a ridge of rolling hills and limestone outcropping, dressed in bedrock, native grasses, wildflowers and the occasional stand of oak and craggy cedar.

This is Texas Hill Country. It starts just below Fort Worth in the north and stretches to the south beyond San Antonio. And just west of Dripping Springs, 38 miles southeast of Austin, lies the 320-acre Avera Ranch.

When the Averas acquired the ranch in the late 1980s, the land was suffering from overgrazing, a loss of native grasses and erosion. Hoping to earn a wildlife exemption, the couple poured energy into restoring the land to its mid-1800s condition, alternating a small herd of cattle and putting in an extensive network of roads and ponds to stop the erosion. In the last 10 years, the land has made an amazing recovery. With that mindset, the Averas came to Matt Bachardy, owner of Matt Bachardy Building Design, to create a home that responded to the site and environment.

The alternative system
Bachardy has been in residential design construction since 1978, focused primarily on high-end custom work. In the 1990s, he became interested in alternative forms of construction. When he discovered that people in his area wanted not only the alternative construction, but greener, site-specific environmental design, he checked out strawbale and rammed earth. Noticing that his clients didn't relate to the "hippie" feel of those systems, Bachardy began investigating building with insulated concrete forms. With established construction standards and decades of commercial use, ICFs have proved much more attractive to his clientele.

"My clients relate to the technological aspect rather than the warm fuzzies of the more earthy materials," Bachardy said. "Concrete is encapsulated in a permanent, leave-in-place form, and it is designed so you can attach any standard finish to it.

"While doing some research on ICFs, I came across a local contractor, Terry Sumter, who had been building with ICFs since the early 1990s. At that time, there wasn't industry-wide acceptance of ICFs and no code approvals such as you have now. Using trial and error, he developed his own bracing system and other tools and techniques. According to Sumter, stick frame's days are numbered.

"The big issue for contractors about alternative construction systems is that if there isn't any local labor who A) have an open mind to it and B) are willing to learn and get experience with it, they remain just interesting ideas. It really boils down to labor availability. Sumter was very hands-on, often personally setting the walls and doing the concrete pouring himself. But he also hired helpers who he trained and kept as his regular crew, so finding experienced labor was not a problem on the Avera project."

The project begins
The site chosen for the Avera house rises 1,550 feet above sea level, one of the highest points in Hays County. Although Windy Hill, as it has been called, has sweeping views from east to west, its main exposure is to the north, risking 80-mile-per-hour wind gusts when a Texas " northern" comes barreling down.

When the Averas linked up with Bachardy, who had worked for their ranch some years earlier, they had no specific design in mind other than the number and function of the rooms - and the conviction that they didn't want a standard house.

"This project was done with the ICF contractor's direct involvement because he was the only one who had built with this system," Bachardy said. "I brought him in really early. As the designs developed, I used his experience with the system to bounce issues off of him. By the time the drawings were done, Sumter was as familiar with them as I was. Once the design was approved by the client, I set everything up and consulted with the engineer on all structural details from foundation and footing designs, through rebar placement and sizing, all the way up through reinforcement of the walls, and sizing of the joists and steel beams. I do all the design, drafting and detail work. Because a lot of the structure is exposed, I wanted it to be aesthetically good-looking as well as structurally sound."

From there, the project manager was in charge of working with Sumter (who built the ICF shell) and coordinating all the other trades. As the site was in a rural area, there were no inspections per se, but Bachardy and his structural engineer were onsite about twice a week, checking the work against the plan specs.

The Avera Ranch house
The total project area measures 5,024 square feet, 2,500 square feet of which is heated. There are three bedrooms with walk-in closets, two full baths, a glass-walled office, a great room, kitchen and dining room. The two-story home is surrounded by a variety of terraces, patios, planters and walled gardens, and an extraordinary water feature.

In line with the clients' focus on the environment and energy-efficient design, the house exterior is finished in concrete, native limestone and Galvalume-coated steel and glass, all of which keep maintenance low. A few surfaces of exposed steel beams were painted for protection from the weather. Stained and scored concrete is used in some floor areas.

Interior drywall is painted with low-VOC paint. Exterior doors and windows are aluminum clad, as are the awnings, and remote-controlled skylights in the roof aid natural ventilation.

"The soil was 6 inches of caliche topsoil over solid rock," Bachardy said. "We basically rock-sawed and jack-hammered into the rock to put in a monolithic slab on grade. I did a GPS survey of the entire site. After I got the schematic layout, I had the surveyor set concrete benchmarks with fixed elevation and in perfect alignment east to west with the sun at this latitude, so I could orient the whole foundation from that.

"The builder trenched all the footings and then the concrete was poured into the footings and slab all at once. The rebar was left sticking up about 3 or 4 feet. Then the block was stacked over the rebar and tied to the block. The whole wall was also poured in one pour."

Bachardy used a 91/4-inch block designed for a 6-inch core. "They are stacked like Legos," he said. "Then I used light-gauge steel and a tensioning turnbuckle to draw the walls together and keep them tight during the pour. The corner block is alternated CMU style. The area is level enough so getting the pump trucks in place was not a problem."

Interior wall studs are made from light-gauge steel. The ceilings are constructed with Thermasteel light-gauge steel-reinforced EPS foam panels. The structural spans use wide-flange steel beams. The roof trusses are wood, providing a ventilated space above the panels. The roof uses 5/8-inch plywood radiant barrier for decking.

Not your ordinary ranch
"The ranch doesn't have a lot of trees," Bachardy said. "One of the reasons I pointed the Averas toward building with insulated concrete was for the thermal performance, as it is so exposed to the blazing summer heat. At the same time, the house was designed with a lot of windows because of the views. The goal was to take in the environment and yet protect it at the same time. Toward that end, the house is tucked into the side of the site, so the breezes coming from the east wash over the hill, picking up the coolness from the valley. For the still days, I designed a kind of cowboy-hat roof line, so it has a 4-foot-plus overhang around the house. That cuts down on the sun on the walls and windows. Also, I laid out the placement of the windows so you can take in most of the views without getting direct solar gain, and we used high performance, low-E glass windows with argon gas, as well."

What HGTV episodes call a "water feature" pales beside the Avera ranch waterscape, which emulates a natural stream and runs on a one-half horsepower motor. All the rocks and plants creating the banks of the stream were harvested off the ranch. "The aesthetics of the sound blend in with landscaping," Bachardy said. "Besides hearing the water flowing, it helps somewhat to cool the air on a summer day."

Perhaps the most unusual feature on the ranch is the system that provides most of the domestic water supply and underlines the Averas' commitment to conservation. Bachardy met the Averas through his allied business using rainwater collection rather than well water as the main water resource. There is a collection lift station built behind the house. Rainwater is collected from the roof, flowing to the lowest point in the complex. The lift station has washing and overflow capacity. A transfer pump is turned on by a float switch whenever it rains. It pumps the water out of that lift station and filters it through a sand filter, sending it uphill to a big cistern. In total, the ranch has 150,000 gallons of rainwater storage and a collection of distribution infrastructure, which Bachardy designed.

"The heating system is hot-water based," Bachardy said. "On the air handlers, we have what amounts to a coil that circulates hot water. We also have a super high-efficiency water heater that is about 96 percent efficient. It delivers 150-degree hot water to the coils, providing domestic hot water and space heating. Even with the cold blasts in winter, with the ICF thermal mass and the concrete floors, there is little variation in inside temperature.

"For HVAC, I had Energywise do a detailed computer analysis for sizing. I chose a standard AC air handling box, with AC coil - the hot water uses a separate coil. There is an advantage over time, even though the heater is more expensive, because you have a piece of equipment that does double duty, while using very little energy. This system also keeps the combustion process out of the air stream, unlike a gas system. The homeowners love the house. Their utility bill runs about $120 a month, even with all the glass."

Public awareness
Bachardy is trying to work himself to the point that he can say no to requests for stick-built projects. He is currently setting up a web site, but relies mostly on referrals and word of mouth for new business. He has found both ends of the spectrum as far as clients' familiarity with ICFs: Some don't know anything and some have done a lot of research, tracking the process in minute detail and understanding the benefits.

"The more forward-looking builders are interested in concrete for residential," Bachardy said. "However, the builder market is money-driven. Now, it is the mid- to-high-end custom client who even considers it, so for builders it is still very much a niche market. If a designer can get more [ICF homes] built and steer clients that are like-minded, show the homes and advertise, people will recognize the benefits more.

"There is much more to an ICF home than structure: It is like living in a sculpture. That house is concerned not just with the interior but with how it relates to the site and how it looks and functions all the way around."